Pulmonary Airflow

ABSTRACT

Devices, systems, and methods for improving airflow within an airway. One example embodiment includes a method for treating a subject. The method includes (1) placing an expandable object into one or more airways of the bronchial tree of the subject, (2) expanding the expandable object within at least one of the one or more airways such that at least a portion of a wall of the one or more airways is expanded, and (3) placing a stent in the airway such that a portion of the stent is adjacent to the portion of the wall of the one or more expanded airways.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/409,875, filed on Jan. 19, 2017, which is a continuation of U.S.patent application Ser. No. 14/852,609, filed on Sep. 13, 2015 andissued on Mar. 14, 2017 as U.S. Pat. No. 9,592,138, both of which areincorporated herein by reference in their entirety.

BACKGROUND

Obstructive lung disease, including emphysema, chronic bronchitis,asthma and others, may lead to various obstructions and/or narrowing ofairways within the bronchial tree. Airways that are affected byobstructive lung disease may include, for example, any of the trachea,main bronchi, lobar bronchi, segmental bronchi, sub-segmental bronchi,bronchioles, conducting bronchioles, terminal bronchioles andrespiratory bronchioles. Airway obstructions may include the formationof mucous in the airways and/or scaring of the airways. Airway narrowingmay be characterized by loss of radial tension of airways, thickening ofthe airway wall, and/or bronchoconstriction, among other examples.Further, obstructive lung disease may lead to breakdown of alveolarwalls.

It becomes increasingly difficult for a patient to exhale as the airwaysor alveoli become damaged. Patients afflicted by obstructive lungdisease may also face loss in muscle strength and an inability toperform common daily activities, among other ill effects. More detailedaspects of obstructive lung disease including additional aspects of thelungs, the bronchial tree, and airways are discussed further below.

There have been many attempts to cure and/or improve damage of thebronchial tree caused by obstructive lung disease. Other attempts havebeen made to relieve the obstruction and/or narrowing caused byobstructive lung disease. Still other attempts have been made to improveairflow into and out of the alveoli of a lung. However, these attemptshave so far been met by many challenges.

Some treatments involve placement of a prosthetic, such as aconventional stent, in the central airways (i.e., the trachea, mainbronchi, lobar bronchi, and/or segmental bronchi) in an attempt tomaintain patency of these airways. Unfortunately, the central airwaysonly contribute a portion of the overall airway obstruction and/orairway narrowing seen in patients with obstructive lung disease.Further, prosthetics, when placed in the bronchial airways, are plaguedby issues of occlusion including the formation of granulation tissue andmucous impaction. Accordingly, treatments that involve the placement ofconventional stents in airways often result in only short term improvedoutcomes for patients because the stent is eventually occluded.

Other treatments involve attempts to bypass an obstructed bronchialairway by forming a perforation through the chest wall into the outerportions of the lung, thereby creating a direct communication (i.e.,bypass tracts) between diseased alveoli and outside of the body. If noother steps are taken, these bypass tracts will close by normal healingor by the formation of granulation tissue. Treating physicians mayattempt to extend the duration of patency by placing a tubular hollowprosthetic in the bypass tract. However, such prosthetics can induce aforeign body reaction and accelerate the formation of granulationtissue, thereby causing the bypass tracts to eventually become occluded.Moreover, such a bypass procedure is difficult to perform, is timeintensive, and is uncomfortable, inconvenient, and debilitating for thepatient.

Yet other treatments involve forming a perforation between selectcentral airways such as the main bronchi or lobar bronchi and thediseased alveoli in an attempt to bypass the obstructed connectingairways. If no other steps are taken, the perforations regularly healclosed, minimizing the long-term effectiveness of such treatments.Attempts have been made to maintain patency of the perforation byplacing supporting stents in the lumen of the perforation. Additionally,the stents may be covered with silicone and/or coated withantiproliferative drugs to minimize the effect of the normal healingresponse and/or the foreign body reaction including granulation tissueformation. Unfortunately, however, these measures are typicallyinadequate and the supporting stents again induce a foreign bodyreaction including granulation tissue formation that often occludes thestent and results in closure of the perforation. Additionally, mucousproduced from glands in the central airways often occludes the stent andresults in closure of the perforation.

These and other problems continue to plague existing treatments forobstructive lung disease, and no reliable way to avoid such problems hasyet been developed. It would therefore be desirable to developtreatments for issues caused by obstructive lung disease—including asexamples obstruction and narrowing of airways of the bronchial tree—thatmore reliably avoid the problems encountered by existing treatments.

SUMMARY

This disclosure includes various devices, systems, and methods usefulfor improving airflow within a bronchial tree and/or into and out of thealveoli of the lung. In some examples, the airways that connect centralairways to alveoli are enlarged so as to improve airflow between thecentral airways and the alveoli. In some cases, the connecting airwaysthat connect the central airways to alveoli may be enlarged beyond theirnormal size to further improve airflow. In still other cases, when theairways are enlarged beyond their normal size, the walls of some of theairways may become perforated allowing communication of additionalalveoli that are adjacent to the connecting airways with the centralairways.

A first aspect of the disclosure involves an open form stent that, whenplaced within a lung of a patient, generally facilitates airflow toand/or from particular alveoli and more central airways, and alsofacilitates a minimization and localization of the formation ofgranulation tissue. Beneficially, the open form stent of the firstaspect also makes use of collateral airflow between the particularalveoli and surrounding alveoli that is normally present in a lung, thatis accentuated in an obstructed lung, and that is further accentuated inan emphysematous lung. In particular, because the open form stentimproves airflow between the particular alveoli and more centralairways, more of the collateral airflow is able to make its way to thecentral airways as well.

A second aspect of the disclosure involves an expandable object that,when placed within a lung of a patient, may expand one or more airway(s)beyond their normal diameter. Expansion of an airway may causeperforation(s) or tear(s) in the wall of the airway, thereby creatingdirect communications between the airway and surrounding alveoli, andmay thereby increase airflow in and out of the airway not only from thealveoli normally connected to the airway but also from alveolisurrounding the airway. In one example the expandable object is adilatory balloon. In another example the expandable object is a dilatorycryo balloon. In another example the expandable object is a wire basket.In another example the expandable object is the open form stent. Otherexamples exist.

A third aspect of the disclosure involves a method for treating apatient using a stent (in some examples, an open-form stent) and anexpandable object. According to such a method, the expandable object maybe used to expand one or more obstructed airways and/or causeperforation(s) or tear(s) (i.e., openings) in the wall of the airway,and then the stent may be placed within the airway to further facilitateairflow within the airway. The stent may be placed for an indefiniteperiod of time, or may be removed after a given period of time.

In some examples, a stent may be used to improve airflow without use ofan expandable object. In other examples, an expandable object may beused to improve airflow without use of a stent.

As discussed in more detail below, this disclosure involves otheraspects as well, some of which include and/or incorporate the threeaspects mentioned above.

One example embodiment includes a method for treating a subject. Themethod includes (1) placing an expandable object into one or moreairways of the bronchial tree of the subject, (2) expanding theexpandable object within at least one of the one or more airways suchthat at least a portion of the wall of the one or more airways isexpanded, and (3) placing a stent in the one or more airways such that aportion of the stent is adjacent to the portion of the wall of the oneor more expanded airways. In some examples, the method involves (1)placing an expandable object into two or more airways of the bronchialtree of the subject, where a first end of the expandable object issituated within a first airway of the bronchial tree and a second end ofthe expandable object is situated within a second airway of thebronchial tree, (2) expanding the expandable object within at least twoof the two or more airways such that at least a portion of a wall of thetwo or more airways is expanded, and (3) placing a stent within the atleast two of the two or more airways such that a portion of the stent isadjacent to the portion of the wall of the two or more expanded airways.

Another example embodiment includes a system used for treating asubject. The system includes (1) an expandable object, (2) a stent, and(3) instructions for improving airflow in one or more airways of abronchial tree of a subject using the expandable object and the stent.The instructions for improving airflow in the airway of the bronchialtree of the subject using the expandable object and the stent mayinclude, in one example: (a) placing an expandable object into one ormore airways of the bronchial tree of the subject, (b) expanding theexpandable object within at least one of the one or more airways suchthat at least a portion of the wall of the one or more airways isexpanded, and (c) placing a stent in the one or more airways such that aportion of the stent is adjacent to the portion of the wall of the oneor more expanded airways.

These as well as other embodiments, aspects, advantages, andalternatives will become apparent to those of ordinary skill in the artby reading the following detailed description, with reference whereappropriate to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows aspects of an example patient.

FIG. 2 shows aspects of a terminal portion of an example bronchial tree.

FIG. 3A shows aspects of an example open-form stent.

FIG. 3B shows aspects of an example open-form stent within an airway.

FIGS. 4A and 4B show aspects of an airway having an example open-formstent placed within the airway.

FIGS. 4C and 4D show aspects of an airway having an example closed-formstent placed within the airway.

FIGS. 5A and 5B show aspects of an example open-form stent.

FIG. 5C shows aspects of an example open-form stent within an airway.

FIGS. 6A and 6B show aspects on an example expandable object.

FIGS. 7A and 7B show aspects of an expandable object within an airway.

FIG. 7C shows aspects of an example expandable object.

FIG. 8 shows an example method for improving airflow in an airway.

FIGS. 9A, 9B, 9C, 9D, 9E, 9F, and 9G show example aspects of examplemethods.

FIGS. 10A, 10B, 10C, 10D, 10E, and 10F show example aspects of examplemethods.

FIG. 11 shows an example method for improving airflow in an airway.

FIG. 12 shows an example method for improving airflow in an airway.

FIG. 13 shows an example treatment protocol.

DETAILED DESCRIPTION

In the following detailed description, reference is made to theaccompanying figures, which form a part thereof. In the figures, similarsymbols typically identify similar components, unless context dictatesotherwise. The illustrative embodiments described in the detaileddescription, figures, and claims are not meant to be limiting. Otherembodiments may be utilized, and other changes may be made, withoutdeparting from the spirit or scope of the subject matter presentedherein. It will be readily understood that aspects of the presentdisclosure, as generally described herein, and illustrated in thefigures, can be arranged, substituted, combined, separated, and/ordesigned in a wide variety of different configurations, all of which arecontemplated herein.

The devices, systems, and methods described herein may be used for thepurpose of improving airflow within a bronchial tree. More particularly,some devices, systems, and methods described herein include stents andexpandable objects that may be used to improve airflow in airways of apatient's bronchial tree. However, it should be understood that such anapplication is but one particular application of the devices, systems,and methods described herein, and that other applications are certainlypossible as well.

The devices, systems, and methods described herein may generally providefor improved airflow in a manner that is relatively efficient,effective, and redundant when compared to other techniques. As oneexample, the devices, systems, and method described herein may minimizegranulation and/or minimize occlusion issues associated with other knowntechniques that involve the use of foreign bodies. The devices, systems,and method described herein may also avoid some discomfort andinconvenience associated with some known techniques that involve the useof bypass paths. Therefore, many of the disadvantages of othertechniques directed at attempts to improve airflow may be avoided.

1. Example Patient

For purposes of example and explanation, FIG. 1 shows aspects of anexample patient 100. As shown, within patient 100 are lungs 102. Lungs102 may generally be accessed by a treating physician via the patient'strachea 104, perhaps using a bronchoscope, catheter, or other suchdelivery device introduced to the patient's trachea through the mouth ornose.

The patient's lungs contain a portion of the patient's bronchial tree106. Bronchial tree 106 includes numerous airways including centralairways such as the right and left main bronchus and the lobar bronchi,intermediary airways such as numerous segmental and sub-segmentalbronchi, and non-central periphery airways such as the bronchioles,conducting bronchioles, terminal bronchioles and respiratorybronchioles, etc., discussed further below.

The example bronchial tree shown also includes a diseased portion 108located at a terminal point of the bronchial tree. In some examplesituations, diseased portion 108 may be understood to be affected by anobstructive lung disease such as emphysema, among other examples.

The diseased portion may be characterized by damage that impairs thepassage of air between airways and the alveoli, and therefore ultimatelyimpairs the passage of gas from the air outside the patient to/from thelungs to/from the patient's blood stream. For example, certain airwayswithin the diseased portion may be occluded, collapsed, and/or otherwiseconstricted. At the same time, alveolar walls within alveoli of thediseased portion may have deteriorated.

To more fully understand the detrimental effects of obstructive lungdisease, a cursory discussion of the workings of the lungs may bebeneficial. One function of the lungs is to permit the exchange of twogasses by removing carbon dioxide from blood and replacing it withoxygen. To facilitate this gaseous exchange, the lungs move oxygen andcarbon dioxide between the air outside the patient's body and blood bybulk conduction through the bronchial tree to the alveoli and diffusionacross a blood gas interface within the patient's alveoli.

The air is brought to the patient's alveoli via airways of the patient'sbronchial tree, housed within the patient's lungs. The bronchial treeincludes branching airways that become narrower, shorter, and morenumerous as they penetrate deeper into the lung. As noted above, thetrachea branches into the right and left main bronchus, which divideinto a multitude of conducting airways starting with the lobar bronchi,intermediary airways such as segmental and sub-segmental bronchi, andperiphery airways such as the bronchioles, conducting bronchioles, andfinally terminal bronchioles.

The terminal bronchioles each gives rise to several respiratorybronchioles, which go on to divide into multiple alveolar ducts, oftenranging in number from two to eleven. FIG. 2 shows aspects of theterminal portion of the example bronchial tree, including examples ofsuch smaller bronchioles.

Example bronchial tree 200 includes bronchiole 202, which divides intoterminal bronchioles 204. Terminal bronchiole 204 then divides intorespiratory bronchioles 206. Also shown are example alveoli 208,containing alveolar sacs 210. As shown, various alveoli 212 may bepresent along the length of a respiratory bronchiole 206 as well.

The terminal bronchioles 204 are the smallest airways that do notcontain alveoli. A function of the bronchi and bronchioles is to provideconducting airways that lead air to and from the alveoli. However, theconducting airways do not contain alveoli and do not take park in gasexchange. Rather, gas exchange takes place in the alveoli that are founddistal to the conducting airways, starting at the respiratorybronchioles.

It is common to refer to, or otherwise characterize, the various airwaysof the bronchial tree according to “generations.” For instance, thetrachea is referred to as “generation 0” of the bronchial tree. Variouslevels of bronchi, including the left and right main bronchi, arereferred to as “generation 1.” The lobar bronchi are referred to as“generation 2.” The segmental bronchi are referred to as “generation 3.”Various bronchioles are referred to “generation 4 though 19.” Terminalbronchioles, for instance, are approximately “generation 14-18.”Respiratory bronchioles, for instance, are approximately “generation16-20.” Further, it is common to refer to the airways extending from thetrachea to the terminal bronchi as “conducting airways.”

Obstructive lung disease, such as emphysema in particular, ischaracterized by irreversible destruction of the alveolar walls thatcontain elastic fibers that maintain radial outward traction on smallairways and are useful in inhalation and exhalation. When these elasticfibers are damaged, these small airways are no longer under radialoutward traction and can collapse, particularly during exhalation. Assuch, when these fibers are damaged, air may be trapped in the lungs andnot be able to be completely expelled during exhalation. Emphysemaresults in hyperinflation (air trapping) of the lung and an inability ofthe person to exhale. In this situation, the individual will bedebilitated since the lungs are unable to perform gas exchange at asatisfactory rate and the lungs are hyperinflated and applying pressureto the chest wall, diaphragm, and surrounding structures.

One further aspect of alveolar wall destruction is that the airflowbetween neighboring air sacs, known as collateral ventilation orcollateral air flow, is increased. However, this alone is of little orno benefit to the patient because air is still unable to flow into andout of the lungs through the collapsed and obstructed airways.

Chronic bronchitis is characterized by excessive mucous production inthe bronchial tree. Usually there is a general increase in bulk(hypertrophy) of the large bronchi and chronic inflammatory changes inthe small airways. Excessive amounts of mucus are found in the airwaysand semisolid plugs of the mucus may occlude small bronchi. Also, thesmall airways are usually narrowed and show inflammatory changes.

The devices, systems, and methods described herein may generally be usedto improve airflow out of hyperinflated alveoli within a diseasedportion 108 of the lung that are affected by obstructive lung diseasesuch as emphysema and/or bronchitis and into central airways of thebronchial tree. Accordingly, the example stents and expandable objectsdescribed more fully below may be delivered to and placed within airwaysthat connect central airways to the distal airways and alveoli ofdiseased portion 108.

2. Example Open-Form Stent

FIG. 3A shows aspects of an example open-form stent 300. As shown theopen-form stent may generally have an open configuration, in the form ofa coil-like or spring-like structure. It may be understood that the coilis characterized by a continuous outer diameter. Herein, the outerdiameter of the coil may sometimes be referred to as an “open-form wall”for purposes of example and explanation. As a result of the open-formconfiguration of the stent, it will be appreciated that no portion ofthe open-form stent entirely isolates a given area of the open-formwall. In other words, the open-form wall comprises a continuously openhelical surface, discussed further below in connection with FIGS. 4A and4B.

FIG. 3B shows aspects of open-form stent 352 in airway 350. Those ofskill in the art will appreciate that surface of airway 350 may becharacterized by a mucociliary structure (or “elevator”) on its innerwall that is capable of clearing mucous within the airway. Themucociliary structure may include cilia that continuously move mucousalong, and ultimately out of, the airway. Because no portion ofopen-form stent 350 entirely isolates a given area of the inner wall ofairway 350, natural mucociliary processes of the airway may generallynot be inhibited when the open-form stent is in place.

As discussed further below with respect to FIGS. 4C and 4D, traditionalclosed-form stents interrupt the function of the mucociliary structureby preventing exposure of the mucous to the mucociliary structurealtogether and/or closing off a given area of the airway wall so thatmucous may not advance further along the airway. However, the open-formstent shown in FIGS. 3A and 3B allows exposure of the airway wall to theinside of the airway even when the stent is in place, and also does nottotally block the mucociliary structure in any one direction. As such,even when the open-form stent is in place, the mucociliary structure maycontinue to facilitate mucuous clearance along a helical pathway thatruns through the center of the coil.

As another advantage, the open-form stent may be characterized by acertain amount of flexibility and recoil, such that the open-form stentwill minimize mechanical toxicity within the airway, especially whenexpanding across multiple airways. Given the flexibility of theopen-form stent, it may bend and move with the airway, and therebyminimize foreign-body response within the airway. As a result, such anopen-form stent will minimize inflammation and will minimize theformation of granulation tissue within the airway. Further, whatinflammation and granulation tissue that forms will be concentrated nearthe contact of the stent with the wall such that air and/or mucous maystill move along the airway in the helical open space of the stent.

As yet another advantage, because the open-form stent is characterizedby an open-form wall that does not close off the exterior of the stentfrom the interior of the stent, the open-form stent may allow forcollateral airflow from side passages, such as alveoli or inducedperforations connecting to other surround alveoli, into the main lumenof the airway.

The open-form stent may be formed of any suitable material. Forinstance, the open-form stent may be formed of a silicone polyestermaterial. Examples include urethane, polyethylene terephthalate (PET),polytetrafluoroethylene (PTFE), and polyetherether ketone (PEEK). Inother cases, the open-form stent may be formed of a metal material.Examples include stainless steel and nitinol. Other examples of suitablematerials exist.

The open-form stent may be coated in one or more suitable coatings. Inone example, the open-form stent may be coated in an antiproliferativeagent such as sirolimus, everolimus, zotarolimus, paclitaxel, taxotere,mitomycin-C, among others. In another example, the open-form stent maybe coated in an antimucous agent such as atropine, ipratropium,tiotropium or a steroid. In yet another example, the open form stent maybe coated in a mucolytic material such as N-acetylcystine or guifensin.In yet another example still, the open-form stent may be coated in ahydrophilic material. Other examples of suitable coatings exist.

As shown in FIG. 3A, example open-form stent 300 has a given length 302,which may be any suitable length and may vary depending on applicationincluding what airway(s) the open-form stent is to ultimately be placed.In one example, length 302 may be between 2 cm to 10 cm in length. Forinstance, length 302 may be approximately 6 cm in length. Other lengthsmay be suitable as well.

As also shown in FIG. 3A, example open-form stent 300 has a givenheight, or diameter 304, which may be any suitable diameter and may varydepending on application including what airway(s) the open-form stent isto ultimately be placed. In one example, diameter 304 may be between 1mm to 10 mm. For instance, the diameter may be between 4 mm to 8 mm. Inother cases, the diameter may be approximately 6 mm. Other diameters maybe suitable as well.

Further, example open-form stent 300 may include a hook 306 on one orboth ends. The hook may be looped back on itself so as to form a closedstructure at one or both ends. Alternatively and/or additionally, theopen-form stent 300 may include a smooth, rounded ball at one or bothends. Such structures as the hook, loop, or ball may be used whenplacing the open-form stent in an airway, to aid the accessibilityand/or manipulability of the open-form stent. Use of such structures mayfurther limit the trauma the ends of the open-stent may cause on tissue.For example, such a structure may further limit the formation ofgranulation tissue or may prevent formation of a pneumothorax if an endof the open-form stent were to come into contact with the visceralpleura, and/or may prevent pain if an end of the open-form stent were tocome into direct or indirect contact with the parietal pleura.

FIG. 4A shows aspects of open-form stent 402 within airway 400. Alsodepicted in FIG. 4A is a continuous helical pathway along the wall ofairway 400 that remains when open-form stent 402 is placed within airway400. As shown by the various arrows in FIG. 4A, a continuous helicalpathway exists along the open-form wall of the open-form stent thatpermits relatively uninterrupted traversal of the inner wall of theairway along the helical pathway. As noted above, mucuous may be clearedalong this helical pathway by the mucociliary structure of airway 400.Of note, although open-form stent 402 is shown within only a singleportion of airway 400, it should be understood that open-form stent 402may extend into other portions of airway 400 and/or may extend intoother airways altogether.

FIG. 4B shows aspects of open-form stent 452 within airway 450. Likeopen-form stent 402, open form-form stent 452 is characterized by acontinuous helical pathway that exists along its open-form wall. Alsodepicted in FIG. 4B is granulation tissue along the structure ofopen-form stent 452, shown as various X indicators along the open-formstent. As shown, the granulation tissue formation is localized along thestructure of the open-form stent itself. As a result, the continuoushelical pathway along the open-form wall remains. Thus, despite theformation of granulation tissue, the mucociliary structure of airway 450is not prevented from functioning to clear mucous from the airway and anuninterrupted pathway for the movement of air along the airway remains.

FIG. 4C shows aspects of closed-form stent 462 within airway 460, asknown in the art. In contrast to the example open-form stent as shown inFIGS. 4A and 4B, closed-form stent 462 does not provide a continuoushelical pathway along the wall of airway 460. Instead, the structure ofclosed-form stent 462, including its pervasive structure along itslength, prevents traversal of the inner wall of the airway. While aparticular example structure is shown in FIG. 4C as a closed-form wireframe, those of skill in the art will appreciate that other knownclosed-form stents exist including stents characterized by solid (ratherthan wire-frame) walls.

FIG. 4D shows aspects of closed-form stent 472 within airway 470. Likeclosed-form stent 462, closed-form stent 472 does not provide acontinuous helical pathway along the wall of airway 470. Also depictedin FIG. 4D is granulation tissue along the structure of closed-formstent 472, shown as various X indicators along the closed-form stent(representative granulation tissue not shown along all structure of theclosed-form stent). As shown, the granulation tissue formation islocalized along the structure of the closed-form stent, but because theclosed-form stent includes pervasive structure along its length, thegranulation tissue formation is also pervasive along the length of theclosed-form stent. Thus, unlike in the case of the open-form stent shownin FIGS. 4A and 4B, the formation of granulation tissue alongclosed-form stent 472 further prevents the mucociliary structure ofairway 470 from functioning to clear mucuous from the airway.

FIGS. 5A-5C show an alternative example open-form stent. FIG. 5A showsan example open-form stent 500, characterized by relatively less turnsper unit length than that shown above with respect to FIGS. 3A and 3B.In one implementation, the coil structure of open-form stent 500 may becombined with at least one additional coil structure to form anopen-form stent that is characterized by at least a double helixstructure.

An example of an example double helix open-form stent 550 is shown inFIG. 5B. As shown, example open-form stent is formed of a first coilstructure 552 and a second coil structure 554. In some embodiments, thefirst coil structure 552 and the second coil structure 554 may connectat one or both ends of the open-form stent thereby creating a loop. Sucha loop may aid in placement or removal and may also eliminate anypotential sharp ends of the first coil 552 and the second coil 554thereby decreasing trauma that the open form stent may cause to theairway and surrounding tissues. This double coil open-form stent canproduce the same area of stent-airway wall contact as a single coilopen-form stent, but produce less angulation of the coil wires relativeto the airway compared to that which is produced by a single coil stent.Thereby, the double coil open-form stent may allow for a more directpathway for the movement of air and mucous along the airway. Inpractice, such a double helix open-form stent may be placed in an airwayof a bronchial tree to improve airflow.

As shown in FIG. 5C, for instance, double helix open-form stent 582 isplaced in airway 580. Of note, although open-form stent 582 is shownwithin only a single portion of airway 580, it should be understood thatopen-form stent may extend into other portions of airway 580 and/or mayextend into other airways altogether.

3. Example Dilatory Balloon

FIG. 6A shows aspects of an example expandable object 600. As shown, theexpandable object may generally be characterized by a resilientlyflexible bulb, or other open body, that encloses an interior space.

Expandable object 600 may have a first end 602 that is closed and asecond end 604 that is open. In another example, however, the first endmay also be open. Either or both open ends may then be coupled to otherextensions or connected objects, such as tubing, that permitcommunication of fluids such as gases and/or liquids into and out of theinterior space of expandable object 600.

The expandable object may be formed of any suitable material. Forinstance, the expandable object may be formed of a one or more orsilicone, polyvinyl chloride (PVC), nylon, polyethylene terephthalate(PET), polyether block amide (PEBAX), mylar, and/or latex. Otherexamples of suitable materials exist.

The expandable object may be coated in any suitable material. Forinstance, the expandable object may be coated in an antiproliferativeagent (such as taxatore, paclitaxel, and/or sirolimus, among otherexamples). Notably, such an antiproliferative agent may generally assistin maintaining the patency of any tear or perforation formed in theairway wall by use of the expandable object. In this way, such anantiproliferative agent may help ensure the effectiveness of atreatment, particularly when the treatment does not involve theplacement of a stent. Additionally and/or alternatively, the expandableobject may be coated in one or more of an antimucous agent, a mucolyticagent, and a hydrophilic agent. Other examples of suitable coatingsexist.

With reference to FIG. 6A, the expandable object 600 is shown in arelaxed state where the expandable object is not expanded. Bycomparison, with reference to FIG. 6B, example expandable object 650 isshown in an expanded state.

As discussed further bellow, in operation the expandable object may beplaced in an airway or multiple connected airways that form a pathwayfrom more central airways to more peripheral airways or alveoli and thenexpanded so as to also expand the airway or airways. As such, at timesthe expandable object may be referred to herein as a “dilatory balloon.”

In some applications, the dilatory balloon may be used to intentionallydilate an airway(s) or portion of connected airways beyond its normal ornatural diameter. In such a situation, the dilatory balloon mayperforate, puncture, or otherwise damage the wall of an airway orportion of connected airways. In some cases, expansion of the dilatoryballoon will operate to form generally longitudinal tears in the wall ofan airway or portion of connected airways. Notably, such longitudinaltears will tend to run largely parallel to blood vessels, whichthemselves tend to run along the length of airways. As a result, traumato blood vessels themselves will be minimized, and so will bleeding beminimized.

FIGS. 7A and 7B show an example expandable object within an airway. Withrespect to FIG. 7A, expandable object 700 is shown, in a relaxed state,introduced within airway 702. With respect to FIG. 7B, expandable object700 is shown, in an expanded state, within airway 702. As shownexpandable object 700 has extended airway 702 beyond its normal size andhas introduced opening 704 into the wall of airway 702. This effect mayoccur in the wall of a single airway or to one or more walls ofconnected airways. Of note, although expandable object 700 is shownwithin only a single portion of airway 702, it should be understood thatexpandable object 700 may extend into other portions of airway 702and/or may extend into other airways altogether.

While the example expandable object is shown in the figures as having aregular shape, other shapes may be possible. For example, the balloonmay taper in size from one end to the other. As another example, theballoon may include a bulbous end that is relatively larger than anotherportion of the balloon body. As another example still, the balloon mayinclude two bulbous ends. As yet another example, the balloon mayinclude one or more irregular implements on its out surface such as aridge or other obtrusion that may concentrate force generated duringpressurization and expansion of the balloon and enable the balloon tomore readily perforate an airway wall when expanded. Irregular shapes ofthe balloon may generally serve the purpose of extending the airway indesired ways so as to introduce desired openings into the airway.

In some applications the use of the dilatory balloon described hereinmay differ from prior uses of expandable objects within the bronchialtree, such as dilatory balloons used in bronchoplasty. For instance,whereas in a bronchoplasty application an expandable object is typicallyplaced in a central airway, the dilatory balloon described herein may beused in more periphery airways such as those described above withrespect to FIG. 2. As another example, whereas in bronchoplastyapplication an expandable object is typically used to expand anobstructed airway to its normal size, the dilatory ballon describedherein may be used to expand the airway beyond its normal size and insome instances produce openings in an airway wall or in one or moreconnected airways. Openings introduced in the airway wall may thereforeaid in improving airflow between alveoli and other more central airways.

Introduction of openings, such as perforations and/or tears, to thesurface of the airway may lead to exposure of additional openings fromthe airway to alveoli. In this way, airflow within the airway to alveolimay be beneficially increased. Moreover, because peripheral airways arecharacterized by relatively few mucous membranes, occlusion of theperforation and/or tears will be minimized.

Introduction of the dilatory balloon into periphery airways for thispurpose may be accomplished using a relatively quick and efficientmedical procedure in which it may be placed directly into the airway,passed through a bronchoscope placed in the trachea or other airways,through a endotracheal tube placed in the trachea, a laryngeal maskairway placed in hypopharynx, among other access methods. In someinstances, the procedure may be accomplished as an outpatient procedure.In this way, the procedure may be significantly more convenient andsignificantly less intrusive than other techniques for improvingairflow.

In one example, the expandable object may take the form of a cryoballoon. FIG. 7C shows some aspects of an example cryo ballon 780coupled, in fluid communication, with delivery catheter 782. As shown,catheter 782 may contain a fluid delivery passage 784 and fluid drainpassage 786. Each of the walls of catheter 782, fluid delivery passage784, and fluid drain passage 786 may be made from materials known tothose skilled in the art. Aspects of example cryo balloon 780 have beensimplified for purposes of example and explanation. Cryo balloon 780 mayinclude other aspects as understood to those skilled in the art.

In use, cryo balloon 780 may be placed within a desired airway or amultiple connected airways of the bronchial tree. Coolant may then bereleased into the balloon from a pressurized cartridge, container,and/or pump (not shown) through fluid delivery passage 784 to cool theairway at a rate appropriate for the application. In some cases, coolantmay be sprayed into the balloon through fluid delivery passage 784, aseparate sprayer, or other suitable elements. The balloon may beinflated (e.g., by coolant) to a desired pressure (corresponding to adesired size). As a result, the temperature of the airway may bedropped. The resultant temperature will be below body temperature and,with potentially improved results below 0° C. and even more potentiallyimproved results significantly below 0° C. By dropping the temperatureof the balloon significantly below 0° C. the temperature of surroundingtissues may also be reduced significantly below 0° C. Reducing thetemperature of surrounding tissues below 0° C. causes desiccation of thetissue and blood in surrounding blood vessels to stop flowing therebydestroying mucous cells in the airway walls, decreasing subsequentgranulation tissue formation, and minimizing bleeding. The coolant maythen later be discharged from the balloon through fluid drain passage786.

The inflation fluid may be any suitable low freezing point liquid suchas an ethanol mixture or saline mixture or a liquefied gas such as N₂Oor CO₂. Liquid N₂ can be used as a general purpose coolant. When N₂ isused, it can be transported to the balloon in the liquid phase where itevaporates at the exit of fluid delivery passage 784 and enters theballoon as a gas. Freon, N₂O gas, and CO₂ gas can also be used ascoolants. Other coolants could be used such as cold saline solution,Fluisol, or a mixture of saline solution and ethanol. Other examples ofcoolants exist.

While an example expandable object is discussed above as taking the formof a dilatory balloon, this is not necessary. The expandable object maytake other forms as well. In one alternative example, the expandableobject may take the form of a wire basket that is capable ofdecompressing and compressing. Such a wire basket may be well suited forcausing perforations and/or tears in an airway wall in addition toexpanding the airway wall.

4. First Example Method

FIG. 8 generally shows an example method 800 for improving airflowwithin an airway.

For clarity, method 800 shown in FIG. 8 may be described herein withreference to the above figures. It should be understood, however, thatthis is for purposes of example and explanation only and that theoperations of the methods should not be limited by these figures. Method800 may include one or more operations, functions, or actions asillustrated by one or more of the blocks in each figure. Although theblocks are illustrated in sequential order, these blocks may also beperformed in parallel, and/or in a different order than those describedherein. Also, the various blocks may be combined into fewer blocks,divided into additional blocks, and/or removed based upon the desiredimplementation.

Method 800 generally involves, at block 802 placing an expandable objectinto one or more airways of a bronchial tree of a subject. Block 804includes expanding the expandable object within the airway. And block806 includes placing a stent in the airway. As shown, method 800 mayadditionally/optionally involve, at block 801 identifying a diseasedarea to be treated.

Each of these blocks is discussed in more detail below.

a. Identify Diseased Area to be Treated

Block 801 involves identifying a diseased area to be treated. Inaccordance with block 801, a treating physician may identify thediseased area of a bronchial tree using any suitable technique includingany such suitable technique known to those of skill in the art. In anexample, the treating physician may identify a diseased area such asarea 108 shown in FIG. 1.

b. Place Expandable Object into Airway of Bronchial Tree of Subject

Block 802 involves placing an expandable object into one or more airwaysof a bronchial tree of a subject. In accordance with block 802, thesubject may be understood with respect to patient 100. In an example,the bronchial tree may be bronchial tree 106, and the one or moreairways, or at least a portion thereof, may be an airway or portion ofconnected airways within diseased region 108 of the lung. In an example,block 802 involves placing the expandable object into the diseased areaidentified with respect to block 801.

In some examples, placing the expandable object may involve placing theexpandable object into two or more airways of the bronchial tree of thesubject. In such a situation, a first end of the expandable object issituated within a first airway of the bronchial tree and a second end ofthe expandable object is situated within a second airway of thebronchial tree.

The expandable object may be any suitable expandable object including,but not limited to, any one of the example expandable objects discussedabove with respect to FIGS. 6A, 6B, 7A, 7B, and 7C.

In one example, the expandable object may include a dilatory balloon.Such a dilatory balloon may, in some instances, be a cryo ballon. In anexample, the dilatory balloon may include a bulbous form on a distalend. In another example, the dilatory balloon may include at least aportion of its outer surface that is non-uniform. For instance, theouter surface may include a ridge and/or other obtrusion to aid in theexpansion and/or formation of openings in an airway wall.

In an example, placing the expandable object may involve placing theexpandable object using a delivery device such as a catheter, guidewire, bronchoscope and the like. In some instances, placing theexpandable object may additionally involve identifying the targeted areaof a diseased lung, and directing the expandable area towards theidentified area such that at least a portion of the expandable object isnear the diseased portion of the lung. As one having skill in the artwill appreciate, the expandable object may be affixed to a distal end ofthe delivery catheter. A treating physician may then introduce theexpandable object into the trachea 104 of the patient. Using thedelivery catheter, the treating physician may then guide the expandableobject through the bronchial tree and into a peripheral airway of thebronchial tree. The distal end of the expandable object may ultimatelybe delivered to a peripheral diseased region 108, and into a respiratorybronchiole 206 while the proximal end of the expandable object remainsin a more proximal airway such as a terminal bronchiole, conductingbronchiole, bronchiole, sub-segmental bronchus, segmental bronchus orlobar bronchus.

Aspects of block 802 are shown with respect to FIGS. 9A and 9B. Withrespect to FIG. 9A, expandable object 900 is shown as being guided intoairway 902. With respect to FIG. 9B, expandable object 900 is shown ashaving been placed in a desired location of airway 902.

As discussed above and further below with respect to FIG. 9G, analternative example placement of an expandable object may involveplacing the expandable object within the bronchial tree such that theexpandable object spans multiple types of airways. For instance, asshown in FIG. 9G, expandable object 912 is placed within bronchial tree910 such that the distal end of expandable object 912 is situated withina respiratory bronchiole and such that the proximal end is extendingproximally into larger and more central airways.

c. Expand Expandable Object within Airway

Block 804 involves expanding the expandable object within the airwaysuch that at least a portion of the airway or a portion of connectedairways is expanded. In some cases, at least one opening is formed in awall of the airway as a result of the expansion of the expandableobject.

In some examples, expanding the expandable object may involve expandingthe expandable object within at least two of two or more airways suchthat at least a portion of a wall of the two or more airways isexpanded.

As discussed above, the expandable object may be expanded by introducingfluid such as liquid and/or gas, into the expandable object. Forinstance, in an example where the expandable object is a cryo balloon,the cryo balloon may be expanded by introducing N₂O into the cryoballoon.

Aspects of block 804 are shown with respect to FIG. 9C. As shown in FIG.9C, expandable object 900 has been expanded such that airway 902 isexpanded beyond its normal size. As a result, in the particular exampleshown, the expandable object has caused airway 902 to tear such that anopening is now present in the airway wall.

While a tear is shown as formed in airway 902, it should be understoodthat it is not necessary to form an opening in all implementations. Insome implementations it may be desirable and/or sufficient to dilate theairway without tearing the airway.

Further, while a single tear is shown as formed in airway 902, it shouldbe understood that more than one tear may be formed. That is, block 804may involve forming at least one opening in the airway wall.

Further, with reference again to FIG. 9G, expandable object 912 may beexpanded such that multiple sections of airways of bronchial tree 910are expanded. In turn, tears and/or perforations may be formed withinmultiple sections of airways.

In some implementations, after the expandable object is expanded, theexpandable object may then be removed. As shown with respect to FIG. 9D,expandable object 900 has been returned to a relaxed state. Expandableobject 900 may then be guided out of the airway, back through thebronchial tree, and out of the patient's trachea.

d. Place Stent in Airway

Block 806 involves placing a stent in the airway such that a portion ofthe stent is adjacent to the portion of the wall of the one or moreexpanded airways. In an implementation where the airway wall was torn inaccordance with block 804, placing the stent may involve placing thestent in the airway such that a portion of the stent is adjacent to atleast a portion of the opening in the wall of the airway.

In some examples, placing a stent may involve placing the stent withinat least two of two or more airways such that a portion of the stent isadjacent to a portion of two or more expanded airways.

The stent may be any suitable stent including, but not limited to, anyone of the open-form stents discussed above with respect to FIGS. 3A,3B, 4A, 4B, 5A, 5B, and 5C.

For instance, at least a portion of the open form stent may include acoil. And in some cases, the stent may include both a first coil and asecond coil.

In one example, the open form stent has an open form wall, as discussedabove. In such an example, for at least a particular length of theopen-form stent, no portion of the open-form wall entirely isolates agiven area of the open-form wall. As such, the open-form wall may have acontinuously open helical surface along its length.

While examples described herein include the placement of an open-formstent, it should be understood that in some cases the method may becarried out using a more traditional closed-form stent. In such cases,block 806 may involve placing a closed form stent.

Aspects of block 806 are shown with respect to FIGS. 9E and 9F. Withrespect to FIG. 9E, open-form stent 904 is shown as being guided intoairway 902. As shown, while being guided into place, open-form stent maybe held in a compressed form to aid in maneuverability through thebronchial tree. With respect to FIG. 9E, open-form stent 904 is shown ashaving been placed in a desired location of airway 902 and permitted toexpand. As shown, open-form stent 904 has been placed adjacent to theopening in airway 902.

Open-form stent 904 may then be left in the airway indefinitely and/oruntil a treating physician determines to remove the open-form stent.Alternatively, the open-form stent may be placed temporarily and removedafter some predetermined amount of time. In this way, removal of theopen-form stent will leave an open tissue conduit between centralairways and the alveoli.

In the example shown above, an embodiment of method 800 is describedwhere the expandable object is removed from the airway before the stentis placed in the airway. However, this is not necessary. In anotherembodiment of method 800, the expandable object may be placed togetherwith the stent. Example aspects of such an embodiment are shown withrespect to FIGS. 10A, 10B, 10C, 10D, 10E, and 10F.

As shown with respect to FIG. 10A, before placing the expandable object1000, the stent 1002 may be positioned so as to encompass at least aportion of the expandable object. In this way, the expandable object1000 and stent 1002 form a package that may together be guided into anairway.

With respect to FIG. 10B, the package of expandable object 1000 andstent 1002 may then be guided into airway 1004. As shown in FIG. 10C,the package of expandable object 1000 and stent 1002 has been placed ina desired location of the airway.

With respect to FIG. 10D, the expandable object 1000 may then beexpanded. As shown, stent 1002 may be arranged so that it increases insize as expandable object 1000 expands. After expansion of expandableobject 1000, an opening in airway 1004 is formed.

With respect to FIG. 10E, the expandable object 1000 may then bereturned to a relaxed state. At the same time, open-form stent 1002 maymaintain a decompressed form, such that it now exerts radial tension onthe airway or portion of connected airways. As shown in FIG. 10E,open-form stent 1004 may exert such radial tension on the airway orportion of connected airways adjacent to at least a portion of the atleast one opening that was formed. Once expandable object 1000 isreturned to a relaxed state, it may then be guided out of the airway,back through the bronchial tree, and out of the patient's trachea.

With respect to FIG. 10F, once expandable object 1000 is removed fromthe airway, stent 1002 may remain in place within airway 1004 or portionof connected airways. Further, in some examples stent 1002 may remain inplace within the bronchial tree such that the stent spans multiple typesof airways. For instance, in some ways similar to expandable object 912shown in FIG. 9G, stent 1002 may be placed within a bronchial tree suchthat the distal end of the stent is situated within a respiratorybronchiole and such that the proximal end is extending proximally intolarger and more central airways.

5. Second Example Method

It should be understood that, while various functions described aboveare described, at times, as performed together as part of the samemethod, this is not necessary. In some cases, for instance, a stent suchas that described herein may be used without the use of an expandableobject. On the other hand, an expandable object such as that describedherein may be used without the use of a stent. Other examples may exist.

FIG. 11 generally shows another example method 1100 for improvingairflow within an airway or portion of a series of connected airways.

For clarity, method 1100 shown in FIG. 11 may be described herein withreference to various other figures. It should be understood, however,that this is for purposes of example and explanation only and that theoperations of the methods should not be limited by these figures. Method1100 may include one or more operations, functions, or actions asillustrated by one or more of the blocks in each figure. Although theblocks are illustrated in sequential order, these blocks may also beperformed in parallel, and/or in a different order than those describedherein. Also, the various blocks may be combined into fewer blocks,divided into additional blocks, and/or removed based upon the desiredimplementation.

Method 1100 generally involves, at block 1102, sizing an open-formstent. Block 1104 includes placing the open form stent.

a. Size Stent

Block 1102 involves sizing a stent. The size of the stent may becharacterized by estimates of both diameter of the stent and length ofthe stent.

The open-form stent may be any suitable stent including, but not limitedto, any one of the open-form stents discussed above with respect toFIGS. 3A, 3B, 4A, 4B, 5A, 5B, and 5C.

In accordance with block 1102, the stent may be sized according to anysuitable technique.

In one example, the stent may be sized based on an approximated size ofan airway that the stent is to be placed into. For instance, a sizecorresponding to an average size of a respiratory bronchiole may beused. As another example, a size corresponding to the diameter of themost proximal airway in which the stent is to be placed may be used.

In another example, the open-form stent may be sized based on an imageof a given patient's bronchial tree. For instance, the patient'sbronchial tree may be imaged prior to placement of the stent using knownimaging techniques and the stent may be sized according to a sizeindicated by the image. Or, for example, distances can be estimated fromimages generated using known imaging techniques of the patient's chestduring the actual procedure.

In yet another example, the stent may be sized using an expandableobject such as an expandable object described elsewhere herein. Forinstance, prior to placement of the stent, the expandable object may beplaced within the airway and expanded. Then, a size of the expandableobject in the expanded state may be used to infer an appropriate sizefor the stent. In one example, a pressure of the expandable object maybe measured when the expandable object is in the expanded state. Thepressure may be measured using a pressure gauge located on the proximalend of a delivery system for the expandable object. The measuredpressure may be correlated to an appropriate size for the stent.

b. Place Open-form Stent

Block 1104 involves placing the stent in one or more airways. Inaccordance with block 1104, the stent may be placed in any suitablemanner. For instance, the stent may be placed in accordance with thedescription above associated with FIGS. 9E and 9F.

6. Third Example Method

FIG. 12 generally shows another example method 1200 for improvingairflow within an airway.

For clarity, method 1200 shown in FIG. 12 may be described herein withreference to various other figures. It should be understood, however,that this is for purposes of example and explanation only and that theoperations of the methods should not be limited by these figures. Method1200 may include one or more operations, functions, or actions asillustrated by one or more of the blocks in each figure. Although theblocks are illustrated in sequential order, these blocks may also beperformed in parallel, and/or in a different order than those describedherein. Also, the various blocks may be combined into fewer blocks,divided into additional blocks, and/or removed based upon the desiredimplementation.

Method 1200 generally involves, at block 1202, placing an expandableobject into one or more airways of a bronchial tree of a subject. Block1204 includes expanding the expandable object from a relaxed state to anexpanded state within at least one of the one or more airways. Block1206 includes returning the expandable object from the expanded state tothe relaxed state. And block 1208 includes removing the expandableobject form the bronchiole.

a. Place Expandable Object into Airway of Bronchial Tree of Subject

Block 1202 involves placing an expandable object into one or moreairways of a bronchial tree of a subject. The expandable object may beplaced using any suitable technique including those described herein.For instance, the expandable object may be placed as shown above withrespect to FIGS. 9A and 9B or FIGS. 10B and 10C.

b. Expand Expandable Object to Expanded State within Airway

Block 1204 involves expanding the expandable object from a relaxed stateto an expanded state within at least one of the one or more airways suchthat at least a portion of the airway or connected airways is expanded.In some cases, at least one opening is formed in a wall of the one ormore airways as a result of the expansion of the expandable object. Theexpandable object may be expanded within the airway using any suitabletechnique including those described herein. For instance, the expandableobject may be expanded as shown above with respect to FIG. 9C and FIG.10D.

In some instances, the expandable object may be sized such that theexpandable object, when expanded, assumes an outer diameter similar tothat described above with reference to the stents.

c. Return Expandable Object to Relaxed State

Block 1206 involves returning the expandable object from the expandedstate to the relaxed state. The expandable object may be returned to therelaxed state using any suitable technique including those describedherein. For instance, the expandable object may be returned to therelaxed state as shown above with respect to FIG. 9D and FIG. 10E.

d. Remove Expandable Object from Airway

Block 1208 involves removing the expandable object from the one or moreairways The expandable object may be removed using any suitabletechnique including those described herein. For instance, the expandableobject may be removed as shown with respect to FIG. 9D and FIG. 10E.

7. Example Treatment Protocol

FIG. 13 generally shows an example treatment protocol 1300 that may beused in conjunction with the various techniques described herein forimproving airflow within an airway. While certain functions aredescribed with respect to treatment protocol 1300, it should beunderstood that additional and/or other functions may be performed aswell.

Treatment protocol 1300 begins at block 1302, where a patient is given apulmonary history and physical. If the pulmonary history (Hx) and/orphysical indicate that there is a possibility of lung disease, theprotocol continues to block 1304.

At block 1304, the patient is given a pulmonary function test (PFT). ThePFT may include a battery of tests including but not limited tospirometry, static lung volume measurement, diffusing capacity forcarbon monoxide, airways resistance, respiratory muscle strength, andarterial blood gases, among other examples.

At block 1306, it is determined whether the patient's ratio of forceexpiratory volume (FEV) in one second to force to vital capacity (FVC)is greater than 0.7. If no, the protocol proceeds to block 1308, whereit ends. If yes, the protocol proceeds to block 1310. Notably, othercriteria could be used for the decision point at block 1306. Forinstance, if there exists evidence of severe hyperinflation (where theratio of residual volume (RV) to total lung capacity (TLC) is greaterthan or equal to 0.65), then the protocol may proceed to block 1310.

At block 1310, the patient is given a CT scan. The CT scan image anddata is then analyzed by the treating physician.

At block 1312, it is determined whether the patient's CT scan chartindicates that the patient has lung disease such as emphysema, whetherhomogeneous or heterogeneous. If no, the protocol proceeds to block1314, where it ends. If yes, the protocol proceeds to block 1316. Insome situations, it may further be determined that there exists noevidence of significant airway disease or no isolated airway diseasewithout concurrent emphysema before proceeding to block 1316.

At block 1315, the treating physician identifies a diseased area to betreated. In accordance with block 1315, a treating physician mayidentify the diseased area of a bronchial tree using any suitabletechnique including any such suitable technique known to those of skillin the art. In an example, the treating physician may identify adiseased area such as area 108 shown in FIG. 1.

At block 1316, the treating physician treats one or more airways withinthe patient's bronchial tree so as to improve airflow. The airway may betreated in accordance to any method for improving airflow within anairway described herein including, for example, one or more of method800, method 1100, and method 1200.

At block 1318, it is determined whether the treatment was successful inimproving airflow. If yes, the protocol proceeds to block 1320 where itends. If no, block 1316 is repeated so as to improve airflow.

8. Example Treatment Protocol

In an embodiment, a system may be provided in accordance with thevarious methods described herein. The system may include one or more ofan expandable object, a stent, and instructions for improving airflow inan airway of a bronchial tree.

The stent may be any of the stents described herein such as thosedescribed with respect to FIGS. 3A, 3B, 4A, 4B, 5A, 5B, and 5C. Theexpandable object may be any of the expandable objects described hereinsuch as those described with respect to FIGS. 6A, 6B, 7A, 7B, and 7C.The instructions for improving airflow may correspond to any of theexample methods for improving airflow described herein such as any ofmethods 800, 1100, and 1200.

The system may further include other objects. One example includes acartridge containing compressed and/or liquefied gas used for expandingthe expandable object. Another example includes a pressure gauge usedfor monitoring the pressure within the expandable object. Yet anotherexample includes one or more delivery catheter used for guiding theexpandable object and/or the stent through the bronchial tree.

9. Conclusion

While various aspects and embodiments have been disclosed herein, otheraspects and embodiments will be apparent to those skilled in the art.The various aspects and embodiments disclosed herein are for purposes ofillustration and are not intended to be limiting, with the true scopeand spirit being indicated by the following claims.

I claim:
 1. A method comprising: identifying a particular portion of anemphysematous lung; expanding the size of one or more airways connectedto the particular portion of the emphysematous lung; and causing theexpanded size of the one or more airways to be maintained.
 2. The methodof claim 1, wherein expanding the size of the one or more airwaysconnected to the particular portion of the emphysematous lung comprises:placing an expandable object into the one or more airways connected tothe particular portion of the emphysematous lung; and after placing theexpandable object, expanding the expandable object.
 3. The method ofclaim 1, wherein causing the expanded size of the one or more airways tobe maintained comprises placing a stent within at least a portion of theone or more airways.
 4. The method of claim 3, wherein the stent is anopen-form stent.
 5. The method of claim 4, wherein, when the open-formstent is placed within at least the portion of the one or more airways,no portion of the open-form stent entirely isolates a given area of awall of the one or more airways.
 6. The method of claim 4, wherein, whenthe open-form stent is placed within at least the portion of the one ormore airways, the open-form stent does not totally block a mucocilliarystructure of the one or more airways in any one direction.
 7. The methodof claim 3, wherein the stent comprises a diameter of between 4millimeter (mm) to 10 mm.
 8. The method of claim 2, wherein theexpandable object comprises a dilatory balloon.
 9. The method of claim8, wherein the dilatory balloon comprises a cryoballoon.
 10. The methodof claim 8, wherein, when expanded, the dilatory balloon comprises adiameter that is greater than a diameter of at least a portion of theone or more airways before the one or more airways are expanded.
 11. Themethod of claim 1, wherein the particular portion of the emphysematouslung comprises at least one alveolar sac, the method further comprising:placing an expandable object such that it extends from the at least onealveolar sac into one or more airways connected to the at least onealveolar sac.
 12. The method of claim 1, wherein the particular portionof the emphysematous lung comprises a terminal bronchiole of theemphysematous lung, the method further comprising: placing an expandableobject such that it extends from the terminal bronchiole of theemphysematous lung into one or more airways connected to the terminalbronchiole of the emphysematous lung.
 13. The method of claim 1, whereinthe particular portion of the emphysematous lung comprises a respiratorybronchiole of the emphysematous lung, the method further comprising:placing an expandable object such that it extends from the respiratorybronchiole of the emphysematous lung into one or more airways connectedto the respiratory bronchiole of the emphysematous lung.
 14. The methodof claim 1, wherein expanding the expandable object comprises expandingthe expandable object such that (a) a diameter of the expandable objectis greater than a diameter of at least a portion of the one or moreairways before the one or more airways are expanded and (b) at least oneopening is formed in at least a portion of a wall of the one or moreconnected airways.
 15. The method of claim 1, wherein the one or moreairways connected to the particular portion of the emphysematous lungcomprises two or more connected airways connected to the particularportion of the emphysematous lung.
 16. The method of claim 15, whereinexpanding the size of the two or more connected airways connected to theparticular portion of the emphysematous lung comprises: placing anexpandable object into the two or more connected airways, wherein adistal end of the expandable object is situated within a first airway ofthe emphysematous lung and a proximal end of the expandable object issituated within a second airway of the emphysematous lung, and whereinthe second airway is a lower generation airway within the emphysematouslung than is the first airway; and after placing the expandable object,expanding the expandable object.
 17. The method of claim 16, whereinmaintaining the increased size of the one or more airways, comprisesplacing a stent within at least a portion of the two or more connectedairways.
 18. The method of claim 1, wherein the particular portion ofthe emphysematous lung is hyperinflated.
 19. A method comprising:identifying a particular portion of an emphysematous lung; expanding thesize of one or more airways that connect the particular portion of theemphysematous lung to an airway that is a segmental bronchus; andcausing the expanded size of the one or more airways to be maintained.20. A method comprising: identifying a particular portion of anemphysematous lung; expanding the size of one or more airways thatconnect the particular portion of the emphysematous lung to an airwaythat is a segmental bronchus; and placing a stent within at least (a)the segmental bronchus and (b) a portion of the one or more airways thatconnect the particular portion of the emphysematous lung to thesegmental bronchus.